Railway and like signaling.



n. w. TARRANT.

RAILWAY AND LIKE SIGNALINGp @APPLICATION FILED APR.20. IBIS.

1 ,%?7,5@5 I Patented Sept. 3, 1918.

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14 VV/TA/ESSES. M/I/EA/TO/f RAILWAY AND LIKE SIGN ALIN G. APPLICATION FILED APR.20. 191a.

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Patented Sept. 3, 1918. I I

maintained so long as the abnormal conditions continue, and consequently serving to prevent accidental restoration of the controlled signal to its normal state (say line clear) during the continuance of such conditions within the system.

The relay ZLbOXG referred to may be regarded as constituting either an electric motor, or a relay such as, for example, that described in U. S. Letters Patent No. 1,168,488 dated January 18, 1916.

In the accompanying drawings, which illustrate diagran'nnatically two arrangements embodying the present invention as applied to a single block-section of a line of rail way, Figures 1 and 2 show an arrangement wherein the two sources of current are separate batteries placed respectively near the opposite ends of the section and con- Inected by a separate line-wire, while Figs.

3 and 1- show an arrangement wherein alternating current 15 derived through transformers from mains extending alongside the permanent way, one of these mains serving as the connection between the secondaries of the respective transformers.

Figs. 1 and 3 each represent the condi tions normally existing in the corresponding system, While Figs. 2 and 41 each indicate the conditions resultin from the entrance of a train into the bloc r-section.

In all the figures, a, b, are the rails of the track within the block-section illustrated; c are the coils of one winding of the relay, and d are the coils of the other winding of the same. The pole-pieces d of the winding d are stationary, whereas the pole-pieces 0 of the winding 0, which are adjacent and opposed to the pole-pieces cl, are pivoted so as to be movable toward and from these stationary pole-pieces and tend to approach the latter under gravity or spring-pressure.

Referring, first, to Figs. 1. and 2, e and f are two separate batteries (of nominally or substantially equal strength) for energizing the relay-windings, the battery 0 being placed toward that end of the block-section near to which the relay is situated, while the battery f is placed toward the opposite end of the section. The negative pole of the battery 0 is connected by a wire 11 to one end of the winding 0 of the relay, the other end of this winding being connected by a wire 12 to the adjacent end of the rail a, while the farther end of the same rail is connected by a wire 13 to the positive pole of the battery f. Similarly, the positive pole of the battery 0 is connected by a wire ll to one end of the winding (Z of the relay, the other end of this winding being connected by a Wire 15 to the adjacent end of the rail 6, while the farther end of the same rail is connected by a wire 16 to the negative pole of the battery 7". The positive pole of the battery f is connected by a line-wire 17 with the wire 14, or

in other words with the positive pole of the battery (2; and a resistance at is interposed between the negative pole of the battery and the rail 6 for a purpose which will be explained hereinafter.

g is an electrically-actuated or governed signal commanding the admission of traflic to the block-section, the electric circuit upon which the condition of the signal is dependent being indicated as fed with current from a battery or other source it. In the circuit of this batteryand the signal are interposed two switches j and 7: which are respectively so controlled by the movable pole-pieces 0 of the winding 0 of the relay that, so Long as both the pole-pieces 0 are held apart from the stationary pole-pieces d of the winding (Z, the switches j and 7c are closed and, the circuit of the battery hand signal 9 being thus completed, the signal is held at line clear as indicated in Fig. 1; Whereas, on either or both of the pole-pieces 0' approaching the pole-pieces d, the circuit of the battery IL and signal 9 is broken at either or both of the switches y and 7c, and'the signal is thus put to line blocked as indicated in Fig. 2.

Z (Fig. 2) represents an axle'and pair of wheels of a train which has entered the block-section and which serves to' connect together electrically the rails a and b.

The resistance m is interposed between the battery f and rail .7) for the purpose of preventing excessive increase of current-value when, owing for example to the presence of an axle and pair of wheels in the block-section as in Fig. 2, the battery f is short-circuited across the rails a and b. The normal value of the resistance at should be so adjusted as to maintain the proportion, between the current-values in the windings c and d respectively, required for normally causing the pole-pieces c to be repelled and held apart from the pole-pieces d, as will now be described with reference to Fig. 1.

That is to say, in normal circumstances (2'. e. when no train is in the block-section, and no other abnormal current-conditions prevail) current from battery f flows from the positive pole of said battery through wires 17 and 14, the winding (Z of the relay, wire 15, rail 6, resistance m, and wire 16, back to the negative pole of battery 7. At the same time current from battery 0 flows from the positive pole of said battery through wires 14:, 17 and 13, rail (4, wire 12, the winding 0 of the relay and wire 11 back to the negative pole of battery 6. The coils c and cl are so wound and mounted that each of the poles 0 has opposite to it a pole (Z of the same sign, while the relative values of the currents by which the coils are respecti vely energized are so adjusted (by means of the resistance m as already stated) that the movable poles c are repelled and held apart from the stationary poles cl in opposition. to gravity or spring-pressure, withthe result that the switches j and 70 are closed andthe signal 9 is held at line clear, as indicated in Fig. 1.

If, now, as indicated inFig. 2, an axle and wheels Z enter the block-section, it will be seen that although the winding 0 remains energized, the current in the winding (Z is reduced to practically m'l. That is to say, whileon the one handthe battery fis shortcircuited through the axle and. wheels Z, current flowing from the battery through wire13, part of raila, the axleandwheels Z, part of rail 1), the resistance m and wire 16, back to battery 7", on the other hand bat tery a will now energize the windingc alone, current flowing from, battery 6 through wires 14, 17 and 13, rail a, wire 12, winding 0, and wire 11, back to battery 0. That the current in winding (Z is now substantially nil results from the fact that with a car axle in the block section the second winding (6 will be short circuited by the wires 17, 13,

track a, axle Z,-track 7),, and wire 15. It willthus be evident that the relative valve-difference between the currents flowing in, the re: spective windings 0 and (Z, which. is necessary for the purpose of maintaining the requisite repulsive force as between the pole-pieces c and (Z is no longer maintained, and consequently the pole-pieces 0 will approach the pole-pieces '(Z andthe switches j and iawill be opened, with the result that the signal 9 will be put to line blocked.

A like result as regards the switches j and 7c and signal 9 will be produced not only if current entirely ceases. toflow in both of the windings 0 and d, but .also ifthe current flowing in one only of the windings ceases or if the ratio between the values of the currents flowing in .the respective,windings is caused to vary beyond what may be termed theworlging limits of said, ratio. Moreover,

as any such disturbance of the current-con ditions within the system (as distinct from total cessation of current in both windings of the relay) will produce a corresponding alteration in the relative strengths of the magnetic fields normally existing between the pole-pieces of the respectivewindings, theresult of the disturbance may even be that the attractive influence of that magnetic field which tends to draw the pole-pieces 0 toward the pole-pieces (1 may become so much more powerful than the repulsive influence of that field which tends to separate said pole-pieces, that the attractive influence of the first-mentioned magnetic field will cooperate with gravity or spring-pressure in positively resisting any attempt to restore the pole-pieces c to normal position.

On referring now to Figs. 3 and 4 it will be seen, by comparing the reference symbols used in corresponding figures, that the arrangement illustrated in Figs. 3 and 4 is similar to that illustrated in Figs. land 2 excepting as regards the batteries 6 and f which, in Figs. 3 and 4, are respectively replaced by the secondary windings c and f of transformers It and F whose primary windings e and f" are fed with alternating current from mains m, 1 extending alongside the track; while the mainy is made to serve in place of theline-wire 17 shown in Figs. 1 and 2. For this latter purpose, that end of the primary to (of thetransformer E) which is connected to the main y is con nected directly, by a wire 18, to the same end ofthe secondary e or to the 'wire 14 leading to the winding (Z of the relay; and similarly, that end of the prin'iaryf (of the transformer F), which is connected to the main 'y is connected directly, by a wire 19, to the same end of the secondary f ortothe wire 13 leading to the rail 0;.

The operation of the arrangement illustrated in Figs. 3 and 4 is similar to that of the arrangement illustrated in Figs. 1 and 3, and may be readily followed by reading, along with Figs. 3 and 1-, the description of the operation given above with reference to Figs. 1 and 2; it being only necessary, in so doing, to substitute the secondaries c and f for the batteries 0 and 7 respectively, andto substitute the wire 19, main 3 and wire 13 for the line-wire 17 Further detailed description of the operation with reference to Figs. 3 and 1 is therefore unnecessary.

It will be observed that the system as a whole involves the use, not of a simple trackcircuit (in the ordinary or accepted sense of a single circuit whereof both rails of the track, being constantly in series with one another, normally form a portion), butof two distinct so-called rail-circuits each of which includes only one of the track-rails in series with one winding of the relay and with a separate source of power; the ratio between the values of the current flowing in the respective windings of the relay being normally substantially constant but being materially altered when the traclcrails are connected together electrically, as for example in consequence of the presence of a train upon the rails.

What I claim is 1. In a system of electric control for railway traflic, the combination with a pair of track-rails and two sources of electric current, of a relay having two separate windings; one end of the one winding of the re lay being connected through the one trackrail to the one pole of one of the sources of current and the other end of the same winding being directly connected to the opposite pole of the other source, while one end of the other winding of the relay is connected to the opposite pole of the first-mentioned source of current through the other trackrail and the other end of said winding is directly connected to the first-mentioned pole of the first source and also to the similar pole of the other source of current.

2. In a system of electric control for railway traflic, the combination with a pair of track-rails, two sources of electric current, and a resistance, of a relay having two separate windings; one end of the one winding of the relay being connected through the one traclcrail to the one pole of one of the sources of current and the other end of the same winding being directly connected to the opposite pole of the other source, while one end of the other winding of the relay is con? nected to the opposite pole of tl1efirstmontioned source of current through the other track-rail and the resistance and the other end of said winding is directly connected to the first-mentioned pole of the first source and also to the similar pole of the other source of current.

3. In a system of electric control for rail-- way traflic, the combination of a pair of track-rails, two sources of electric current, a resistance, a relay, two separate windings on said relay, pole-pieces for each winding of the relay, the pole-pieces of the one winding being opposed to and. movable toward. and from the respectively adjacent polepieces of the other winding and the respective windings being wound for producing normally a state oi. magnetic repulsion between each pole of the one winding and the opposed pole of the other winding, an electr cally-controlled signal, and electric switches interposed in series in the circuit for controlling said signal, said switches being adapted to be controlled by the movable pole-pieces of the relay; one end of the one winding of the relay being connected through the one track-rail to the one pole of one of the sources of current and the other end of the same winding being directly connected to the opposite pole of the other-source, while one end of theother winding of the relay is connected to the opposite pole of the first-mentioned source of current through the other track-rail and the resistance and the other end of said winding is directly connected to the first-mentioned pole of the first source and also to the similar pole of the other source of current.

4. In a system of electric control for railway tra'flic, the combination of a pair of tracks-ails, two sources of electric current, a resistance,a relay, two separate windings on said relay, pole-pieces for each winding of the relay, the pole-pieces of the one winding being opposed to and movable toward and from the respectively adjacent pole pieces of the other winding and the respective windings beingwound for producing normally a state of magnetic repulsion between each pole of the one winding and the opposed pole of the other winding, an electricallycontrolled signal, and electric switches interposed in series in the circuit for controlling said signal, said switches being normally held closed by the movable polepieces of the relay; one end of the one winding of the relay being connected through the one track-rail to the one pole of one of the Sources of current and the other end of the same winding being directly connected to the opposite pole ot the other source, while oneend of the other winding of the relay is connected to the opposite pole of the firstmentioned source of current through the other track-rail and the resistance and the other end of said winding is directly connected to the first-mentioned pole of the first source and also to the similar pole of the other source of current.

' REUBEN WVILLIAM TARRANT.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents.

Washln gton, D. G. 

